Parisite-(La), ideally CaLa (CO F , a new mineral from ... · 96 production of rutilated quartz,...
Transcript of Parisite-(La), ideally CaLa (CO F , a new mineral from ... · 96 production of rutilated quartz,...
Parisite-(La), ideally CaLa2(CO3)3F2, a new mineral from 1
Novo Horizonte, Bahia, Brazil. 2
3
Luiz A. D. Menezes Filho1, 4
Mario L. S. C. Chaves1, 5
Nikita V. Chukanov2, 6
Daniel Atencio3, 7
Ricardo Scholz4, 8
Igor Pekov5, 9
Geraldo Magela da Costa6, 10
Shaunna M. Morrison7, 11
Marcelo B. Andrade8, 12
Erico T.F. Freitas9, 13
Robert T. Downs7, 14
Dmitriy I. Belakovskiy10 15
16 1Universidade Federal de Minas Gerais (UFMG), Instituto de Geociências, Departamento de 17
Geologia, Avenida Antônio Carlos, 6627, 31270-901, Belo Horizonte, MG, Brazil 18 2Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, 19
Moscow region, 142432 Russia 20 3Universidade de São Paulo, Instituto de Geociências, Rua do Lago 562, 05508-080, São Paulo, 21
Brazil 22 4Universidade Federal de Ouro Preto (UFOP), Escola de Minas, Departamento de Geologia, 23
Campus Morro do Cruzeiro, 35400-000, Ouro Preto, MG, Brazil 24 5Faculty of Geology, Moscow State University, Vorobievy Gory, Moscow, 119991 Russia 25
6Universidade Federal de Ouro Preto (UFOP), Instituto de Ciências Exatas e Biológicas, 26
Departamento de Química, Campus Morro do Cruzeiro, 35400-000, Ouro Preto, MG, Brazil 27 7Department of Geosciences, University of Arizona, 1040 E. 4th Street, Tucson, Arizona 85721, 28
U.S.A. 29
8University of São Paulo, São Carlos Institute of Physics, PO Box 369, 13560-970, São Carlos, 30
SP, Brazil 31 9Universidade Federal de Minas Gerais (UFMG), Centro de Microscopia, Avenida Antônio 32
Carlos, 6627, 31270-901, Belo Horizonte, MG, Brazil 33 10Fersman Mineralogical Museum of Russian Academy of Sciences, Leninskiy Prospekt 18-2, 34
Moscow, 119071 Russia 35
36
37
38
ABSTRACT 39
40
Parisite-(La) (IMA number 2016-031), ideally CaLa2(CO3)3F2, occurs in a hydrothermal 41
vein crosscutting a metarhyolite of the Rio dos Remédios Group, at the Mula mine, Tapera 42
village, Novo Horizonte county, Bahia, Brazil, associated with hematite, rutile, almeidaite, 43
fluocerite-(Ce), brockite, monazite-(La), rhabdophane-(La), and bastnäsite-(La). Parisite-(La) 44
occurs as residual nuclei (up to 5 mm) in steep doubly-terminated pseudo-hexagonal pyramidal 45
crystals (up to 8.2 cm). Parisite-(La) is transparent, yellow-green to white, with white streak, and 46
displays a vitreous (when yellow-green) to dull (when white) lustre. Cleavage is distinct on 47
pseudo-{001}; fracture is laminated, conchoidal, or uneven. The Mohs hardness is 4 to 5, and it is 48
brittle. Calculated density is 4.273 g cm-3. Parisite-(La) is pseudo-uniaxial (+), ω = 1.670(2), ε = 49
1.782(5) (589 nm). The empirical formula normalized on the basis of 11 (O + F) pfu is 50
Ca0.98(La0.83Nd0.51Ce0.37Pr0.16Sm0.04Y0.03)Σ=1.94C3.03O8.91F2.09. The IR spectrum confirms the 51
absence of OH groups. Single-crystal X-ray studies gave the following results: monoclinic 52
(pseudo-trigonal), space group: C2, Cm, or C2/m, a = 12.356(1) Å, b = 7.1368(7) Å, c = 53
28.299(3) Å, β = 98.342(4)º, V = 2469.1(4) Å3, Z = 12. Parisite-(La) is the La-dominant analogue 54
of parisite-(Ce). 55
56
Keywords: Parisite-(La), new mineral, rare-earth fluorocarbonate, Mula mine, Novo Horizonte, 57
Bahia, Brazil 58
59
60
61
INTRODUCTION 62
63
Parisite-(La) is the La-dominant analogue of parisite-(Ce). Minerals with a chemical 64
composition consistent with that of parisite-(La) were reported in several studies from different 65
localities: Třebíč durbachite massif, SW Moravia, Czech Republic (Sulovský 2001); at a 66
metabauxite/marble interface in the eastern part of Samos island, Greece (Theye et al. 2003); 67
alkaline rocks in Romania (Hirtopanu 2006, Hirtopanu et al. 2015); Cerro Boggiani massif, Alto 68
Paraguay Province, Paraguay (Enrich et al. 2010); Bear Lodge carbonatite, Wyoming, USA 69
(Moore et al. 2015). Parisite-(Nd) is also reported in literature as a mineral without IMA approval 70
(Jambor et al. 1988). 71
Parisite-(La) has been approved as a new mineral species by the Commission of New 72
Minerals, Nomenclature and Classification (CNMNC) of the International Mineralogical 73
Association (IMA 2016-031). The type specimen of parisite-(La) is deposited in the 74
mineralogical collection of the Museu de Geociências, Instituto de Geociências, Universidade de 75
São Paulo, Rua do Lago, 562, 05508-080 - São Paulo, SP, Brazil, with the registration number 76
DR1032 (a part of the holotype), and at the University of Arizona Mineral Museum (RRUFF 77
Project deposition # R130687). 78
79
80
OCCURRENCE 81
82 Parisite-(La) occurs in a late-stage hydrothermal vein crosscutting metarhyolites, at the 83
Mula mine, Tapera village, Novo Horizonte, State of Bahia, Brazil (12°48’28”S; 42°10’04”W). 84
The metarhyolites, together with metadacites and meta-andesites, constitute the Rio dos 85
Remédios Group, a package of metavolcanic acid rocks formed as a result of peraluminous and 86
alkaline magmatism during a continental rift which opened ~1.75 Ga (Teixeira 2005, Martins et 87
al. 2008). This group crops out in an area of about 35 × 10 km2 and is one of the lithologic 88
members of a larger package of metasedimentary and locally metavolcanic rocks called Serra do 89
Espinhaço that extends N-S for about 1200 km from the center of Minas Gerais to the northern 90
reaches of Bahia state (Figure 1). The evolution of the sedimentary basin in this region occurred 91
in several stages during the Mesoproterozoic (~1.7-1.2 Ga) and during subsequent 92
metamorphism, folding and fracturing, during the Brasiliano Cycle of the Neoproterozoic (630 - 93
490 Ma, according to Pedrosa-Soares et al. 2011). During the Brasiliano event, swarms of 94
hydrothermal quartz veins were generated. These have been exploited at Novo Horizonte for the 95
production of rutilated quartz, barite and gold. Martins et al. (2008) reported muscovite ages of 96
404 and 490 Ma in altered metarhyolites close to these veins, confirming their formation during 97
the Brasiliano event. Parisite-(La) is associated with almeidaite (its type locality is also the Mula 98
mine: Menezes Filho et al. 2015), hematite, rutile, fluocerite-(Ce), brockite, monazite-(La), 99
rhabdophane-(La) and bastnäsite-(La). The pit of the Mula mine is composed of brecciated quartz 100
veins cemented by chalcedony. The veins show a stockwork pattern, which is typical of hydraulic 101
fracturing processes, and are partially kaolinized; their orientation is NNW-SSE, with a thickness 102
of up to 2 m. 103
104
105
APPEARANCE and PHYSICAL PROPERTIES 106
107 Parisite-(La) occurs as residual nuclei (up to 5 mm) in doubly-terminated pseudo-108
hexagonal pyramidal crystals (up to 8.2 cm) with corrugated faces (Figure 2a). The crystals 109
apparently do not differ from what is usually described for parisite-(Ce): acute dipyramids with 110
horizontally striated faces, terminated by pinacoid. The pinacoid faces are cleavage planes. The 111
crystals are prismatic in appearance due to oscillatory combination of steep pyramids, but true 112
prism faces are lacking or very small. However real forms of parisite-(La) can be pedion, 113
pinacoid and sphenoid if the space group is C2, pedion, pinacoid and dome if Cm, pinacoid and 114
prism if C2/m.These crystals were partially replaced by bastnäsite-(La), monazite-(La), and 115
rhabdophane-(La). Crusts consisting of microcrystals of parisite-(La) also occur (Figure 2b). 116
Parisite-(La) is transparent, yellow-green to white, with white streak, and displays a 117
vitreous (when yellow-green) to dull (when white) lustre. It is non-fluorescent under both 118
shortwave (254 nm) and longwave (366 nm) ultraviolet radiation. Cleavage is distinct on pseudo-119
{001} and parting was not observed; fracture is laminated, conchoidal, or uneven. The Mohs 120
hardness is between 4 and 5, and the mineral is brittle. Density was not measured; calculated 121
density is 4.273 g cm-3 using the empirical formula. In transmitted light parisite-(La) is 122
colourless, pseudo-uniaxial (+), ω = 1.670(2), ε = 1.782(5) (589 nm). Pleochroism was not 123
observed. 124
125
126
INFRARED and RAMAN SPECTROSCOPY 127
128
In order to obtain infrared (IR) absorption spectra, powdered samples were mixed with 129
anhydrous KBr, pelletized, and analyzed using an ALPHA FTIR spectrometer (Bruker Optics) 130
with the resolution of 4 cm–1 in the wavenumber range from 360 to 3800 cm–1; 16 scans were 131
obtained. The IR spectrum of an analogous pellet of pure KBr was used as a reference. The 132
assignments of IR bands have been made in accordance with Adler and Kerr (1963), White 133
(1974), and Nakamoto (1997, 2009). 134
The IR spectrum of parisite-(La) is close to that of parisite-(Ce) (Figure 3). Weak IR 135
bands in the range 1700–3000 cm–1 correspond to overtones and combination modes. The other 136
bands are assigned as follows (cm–1; w – weak band, s – strong band, sh – shoulder): 1454s, 137
1430sh (degenerate asymmetric C–O-stretching vibrations), 1089w, 1081w (non-degenerate 138
symmetric C–O-stretching vibrations), 871s, 850sh (out-of-plane bending vibrations of the 139
carbonate ion triangles), 746w, 734w (in-plane bending vibrations of the carbonate ion triangles), 140
679w, 602w (presumably, overtones and/or combination modes), 368 (lattice mode involving 141
Ca–O- or REE–O-stretching vibrations). Bands in the range 3000-3800 cm–1 are not observed, 142
which indicates the absence of OH groups. 143
Raman spectrum of parisite-(La) (Figure 4) was collected on a randomly oriented crystal at 144
100% of 150 mW on a Thermo Almega microRaman system, using a 532 nm solid-state laser, 145
confocal Olympus optics with a 10x objective, and a thermoelectrically cooled CCD detector. 146
The laser was partially polarized with 4 cm-1 resolution and a spot size of 1 µm. The peak at 1428 147
cm–1 corresponds to the v3 asymmetric stretching mode of CO32– anions. Symmetric C–O 148
stretching modes are represented by the bands at 1081, 1091, and 1098 cm–1. The bands at 737 149
and 871 cm–1 correspond to in-plane and out-of-plane vibrations of CO32–, respectively. The 150
bands at 600 and 970 cm–1 may be due to any vibrations involving F– anions. Bands with 151
wavenumbers below 500 cm–1 are attributed to lattice modes. The tentative assignment of Raman 152
bands is based on previous studies (Frost & Dickfos 2007, Guastoni et al. 2010, Frost et al. 153
2013). All peaks above 1500 cm-1 are due to fluorescence. This effect is typical for REE 154
compounds (see e. g. Betancourtt 2003) 155
156
157
CHEMICAL DATA 158
159
Chemical analyses (25) were carried out using a Cameca SX100 microprobe (WDS mode, 160
25 kV, 40 nA, beam diameter 5 µm) at the Department of Geosciences, University of Arizona, 161
Tucson, Arizona, U.S.A. H2O was not analysed because of the absence of bands corresponding to 162
O–H vibrations in the IR spectrum. The thermogravimetric (TG) curve of parisite-(La) in 163
nitrogen atmosphere is given in Figure 5. The second step in the TG curve may be due to the 164
decomposition of an intermediate carbonate. Fluorine is not lost during the heating because CaF2 165
melts above 1400°C without decomposition and REEF3 do not decompose into elements below 166
1200°C (Ranieri et al. 2008). The formula corresponding to CO2 content of 23.68% obtained 167
experimentally from TG data is is not charge balanced. This weight loss is slightly less than 168
24.50 wt% CO2 calculated for formula neutrality. Mean analytical results are given in Table 1. 169
The empirical formula normalized on the basis of 11 (O + F) pfu is 170
Ca0.98(La0.83Nd0.51Ce0.37Pr0.16Sm0.04Y0.03)Σ=1.94C3.03O8.91F2.09, where CO2 was constrained to 171
24.50% for charge neutrality. The idealized formula is CaLa2(CO3)3F2, which requires: La2O3 172
60.80, CaO 10.46, CO2 24.63, F 7.09, O=F -2.98, total 100.00wt.%. 173
An additional sample was measured at the Instituto de Geociências, Universidade Federal 174
de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. Chemical analyses (7) were carried out 175
using a Jeol JXA8900R electron microprobe (WDS mode, 15 kV, 20 nA, beam diameter 5 µm). 176
Mean analytical results are given in Table 1. The empirical formula normalized on the basis of 11 177
(O + F) pfu is Ca0.91(La0.82Nd0.47Ce0.43Pr0.26Sm0.04Y0.02)Σ=2.04(CO3)3.03F1.91, where CO2 was 178
constrained to 24.70% for charge neutrality. 179
180
181
CRYSTALLOGRAPHY 182
183
Single-crystal X-ray diffraction studies and Convergent-Beam Electron Diffraction 184
(CBED) analysis performed under TEM indicated monoclinic symmetry (pseudo-trigonal) and 185
systematic absences compatible with space groups C2(#5), Cm(#8), C2/m (#12). Single-crystal 186
X-ray diffraction studies carried out using a Bruker APEX2 CCD automated diffractometer with 187
graphite-monochromatized MoKα (λ = 0.71073 Å) radiation gave the following results: a = 188
12.356(1) Å, b = 7.1368(7) Å, c = 28.299(3) Å, β = 98.342(4)º, V = 2469.1(4) Å3, Z = 12. The a : 189
b : c ratio calculated from the unit cell parameters is 1.7313 : 1 : 3.9652. Gladstone-Dale 190
compatibility is -0.046 (good) for the chemical analysis made in Arizona and -0.032 (excellent) 191
for the chemical analysis made in Minas Gerais. 192
We confirmed that the space groups C2/c(#15) and Cc (#9) cited by Ni et al. (2000) were 193
not consistent for parisite-(La). The space group C2/c (#15) analysis show 816 reflections 194
satisfying systematic absence conditions with an average I/s (I) of 2.07 (21518 reflections read) 195
and for the space group Cc (#9), there are 789 reflections with an average I/s(I) of 2.11 at the 196
same conditions (20612 reflections read). 197
For TEM studies, the sample was ground in an agate mortar and dispersed in a small 198
volume (1 mL) of isopropanol. The suspension was dropped onto the carbon-coated Cu-TEM 199
grid (300 mesh), and placed in a desiccator before TEM analysis. Convergent-Beam Electron 200
Diffraction (CBED) and Nano-Beam Electron Diffraction (NBD) were performed by using a 201
Tecnai G2-20 TEM (FEI), with LaB6 filament, operated at 200 kV, at the Center of Microscopy 202
at UFMG, Belo Horizonte, Brazil. The diffraction patterns were recorded by using a side-203
mounted ES500W Erlangshen CCD camera (Gatan). The CBED patterns were performed using a 204
convergence semi-angle of 1.3 mrad, with a beam size of approximately 20 nm, and the NBD 205
conditions were achieved by slightly spreading the C2 condenser lens to obtain a nearly parallel 206
narrow beam. 207
In order to deduce the crystal system, the Bravais lattice, and the possible space group, 208
electron diffraction experiments were carried out following Morniroli and Steeds (1992), 209
Redjaïmia and Morniroli (1994), Jacob et al. (2012), and Morniroli (2013). A suitable area of the 210
sample was illuminated by a focused narrow beam under the TEM. Observations of CBED 211
patterns were done while the sample was being tilted around a chosen Kikuchi line, or a row 212
containing reflections, which passed through the origin of the reciprocal lattice. Several zone axis 213
patterns (ZAPs) were recorded in the CCD until the ZAP of highest “net”-symmetry had been 214
found. The “net”-symmetry takes into account the position of the reflections observed in the 215
diffraction pattern, not their intensity. It is defined as the symmetry of the spots “net” displayed 216
in the zeroth order Laue zone (ZOLZ) and the whole pattern (WP), which includes the ZOLZ and 217
first order Laue zone (FOLZ) (Morniroli and Steeds 1992; Jacob et al. 2012). Following 218
Morniroli and Steeds (1992), the “net”-symmetry is here referred as “(ZOLZ)WP” symmetry – 219
the (ZOLZ) symmetry is put in brackets henceforth in order to distinguish it from the WP’s. 220
The identification of the monoclinic crystal system was achieved by observing the ZAP of 221
highest “net”-symmetry shown in Figure 6. The two perpendicular axes drawn in the pattern 222
(Figure 6) indicate 2 mirrors, and also 2-fold axes, for the spots net shown in the ZOLZ, therefore 223
the symmetry is (2mm). The vertical axis shown in Figure 6, however, is not a mirror for the WP, 224
but the horizontal one. So the “net”-symmetry observed in this ZAP is (2mm)m. Comparisons 225
with the Atlas of Electron Diffraction Zone-Axis Pattern (Morniroli 2013) showed that the ZAP 226
shown in Figure 6 corresponds to the [u0w] zone axis for the monoclinic system. 227
The non-primitive mS (mA or mB) Bravais lattice was deduced by comparing the features 228
displayed in the diffraction pattern shown in Figure 7 with the typical ZAPs for the monoclinic 229
crystal system (Morniroli 2013). The Figure 7.a shows the ZOLZ reflections of the either [010]b 230
or [001]c zone axis, on which two symmetry axes are drawn – the subscripts b and c stand for 231
unique axis b and c, respectively. These non-perpendicular axes (beta* or gamma* equal 89.18o) 232
indicate the 2-fold symmetry (2) for the spots net seen in the ZOLZ. The FOLZ reflections were 233
not easily observed at first, so the electron beam was tilted along each axis until the FOLZ 234
reflection could be seen at the microscope screen as shown in Figures 7.b and 7.c. From the 235
observation of the FOLZ reflections the symmetry of the WP was taken as 2-fold. So the “net”-236
symmetry of this ZAP concluded as (2)2. This is the exact zone axis pattern required for the 237
identification of the Bravais lattice for the monoclinic system (Morniroli 2013). 238
The narrow parallelograms drawn in the ZOLZ and FOLZ reflections shown in Figure 7 239
correspond to the “unit” cell in the reciprocal space. This “unit” cell indicates the periodicity of 240
reflections in the spots net in the diffraction pattern. As can be seen in Figure 6, there is a relative 241
shift of the “unit” cell in the FOLZ compared to the ZOLZ. It means that the Bravais lattice of the 242
Parisite-(La) crystal is non-primitive (Morniroli and Steeds 1992; Jacob et al. 2012). Therefore, 243
the Bravais lattice is mS (mA or mB). 244
The lack of periodicity differences between ZOLZ and FOLZ reflections is an evidence 245
that there are no glide planes parallel to [010]b or [001]c (Morniroli and Steeds 1992; Jacob et al. 246
2012) as reported by Ni et al (2000) for parisite-(Ce). It was not possible to deduce the screw axis 247
perpendicular to the zone axis pattern [u0w] shown in Figure 6. The possible 21 screw axis 248
perpendicular to that particular zone axis could be related to the forbidden reflections in the row 249
defined by any of the symmetry axes shown in Figure 6. The forbidden nodes would appear, 250
however, due a double diffraction effect. This could be checked out by tilting the beam around 251
the symmetry axis shown in Figure 6 in order to decrease the intensity of the likely forbidden 252
reflections (Morniroli and Steeds 1992), but it has been not verified during measurements. 253
Moreover, the absence of glide planes parallel to [010]b or [001]c are consistent with the possible 254
extinction symbols, A1-1b or B11-c. From the comparisons of the features observed in the 255
experimental ZAPs with the typical theoretical diffraction patterns (Morniroli 2013), the possible 256
space groups are A121 (#5), A1m1 (#8), A12/m1 (#12), B112 (#5), B11m (#8) or B112/m (#12), 257
alternative settings of the space groups C2(#5), Cm(#8), C2/m (#12). 258
Unfortunately, despite determining monoclinic unit-cell parameters from the single-259
crystal pattern, we could not obtain single-crystal data suitable for the structure refinement. Thin 260
inclusions are visible under the microscope. Possible they are the main cause of the absence of 261
single crystals suitable for structural investigations. Inclusions of synchysite, röntgenite or 262
bastnäsite microblocks are typical for parisite in general. 263
X-ray powder diffraction data (Table 2) were obtained using a Rigaku R-AXIS Rapid II 264
single-crystal diffractometer equipped with cylindrical image plate detector using Debye-Scherrer 265
geometry (d = 127.4 mm; CoKα-radiation). Parameters of monoclinic unit cell refined from 266
powder data are: a = 12.323(7), b = 7.121(2), c = 28.28(1) Å, β = 98.33(4)º, V = 2456(3) Å3. 267
268
269
DISCUSSION 270
271
The second most abundant REE in parisite-(La) from Mula mine is Nd, not Ce. On a 272
chondrite-normalized plot there would be a marked negative Ce anomaly. One hypothesis about 273
the conditions of formation could be that the fluids that transported REE had leached them in a 274
mildly oxidizing environment, where Ce was partially oxidized to Ce4+ and thus remained 275
immobile. The resulting solution would be depleted in Ce. For the other five parisite-(La) 276
occurrences quoted in the literature, neither crystallographic nor chemical data are presented. The 277
only exception is a partial chemical analysis for parisite-(La) from Třebíč durbachite massif, SW 278
Moravia, Czech Republic (Sulovský 2001): La2O3 28.68, Ce2O3 24.07, Nd2O3 4.01, CaO 10.22, 279
SO3 0.98, F 6.38, O=F -2.67, total 71.64 wt.%. The calculated formula is 280
Ca1.01(La0.97Ce0.81Nd0.13)Σ1.91(CO3)2.89(SO4)0.07F1.84. In this case Ce is the second most abundant 281
REE and the conditions of formation differ from that of parisite-(La) from Mula mine. 282
283
284
ACKNOWLEDGEMENTS 285
286
We acknowledge the Brazilian agencies FAPESP (processes 2014/50819-9 and 287
2013/03487-8), CNPq, and Finep for financial support, all members of the IMA Commission on 288
New Minerals, Nomenclature and Classification, the Principal Editor Peter Williams, the 289
reviewers Fernando Colombo, Peter Leverett and an anonymous for their helpful suggestions and 290
comments. M. Chaves thanks to CNPq (grant No. 305492/2013-6) and R. Scholz thanks to CNPq 291
and FAPEMIG (respectively grant No. 305284/2015-0 and grant APQ-01448-15). 292
293
294
REFERENCES 295
296 Adler, H.H and Kerr, P.F. (1963) lnfrared spectra, symmetry and structure relations of some 297
carbonate minerals. American Mineralogist, 48, 839-853 298
Betancourtt, V.M.R. (2003) Raman Spectroscopic Study of High Temperature Rare Earth Metal - 299
Rare Earth Halide Solutions: Ln-LnX3- and LnX2-LnX3-(LiX-KX)eu Systems (Ln: Nd, Ce; 300
X: Cl, I). Dr. Sci. thesis. Faculty of Chemistry and Biosciences, Karlsruhe University. 301
Cheang, K. (1977) Structure and Polytypism in Synchysite and Parisite from Mont St. Hilaire, 302
Quebec. M.S. thesis, Carleton University, Ottawa, Canada. 303
Enrich, G.E.R., Gomes, C.B., and Ruberti, E. (2010) Química mineral de carbonatos de 304
elementos terras raras em nefelina sienitos e fonólitos agpaíticos do maciço de Cerro 305
Boggiani, Província Alto Paraguay, Paraguai. In: X Congresso de Geoquímica dos Países de 306
Língua Portuguesa, 2010, Porto. Actas, 2010. v. CD-rom. p. 223-227. 307
Flink, G. (1901) Part I. On the minerals from Narsarsuk on the Firth of Tunugdliarfik in Southern 308
Greenland. Parisite. Meddelelser om Grønland, 24, 29-42. 309
Frost, R.L. and Dickfos, M.J. (2007) Raman spectroscopy of halogen-containing carbonates 310
Journal of Raman Spectroscopy, 38, 1516–1522. 311
Frost, R.L., López, A., Scholz, R., Xi, Y., and Belotti, F.M. (2013) Infrared and Raman 312
spectroscopic characterization of the carbonate mineral huanghoite – And in comparison 313
with selected rare earth carbonates. Journal of Molecular Structure, 1051, 221-225. 314
Guastoni, A., Kondo, D., and Nestola, F. (2010) Bastnäsite-(Ce) and parisite-(Ce) from Mt. 315
Malosa, Malawi. Gems & Gemology, 46, 42-46. 316
Hirtopanu, P. (2006) One hundred minerals for one hundred years (dedicated to the Centennial of 317
the Geological Institute of Romania), 3rd Conference on Mineral Sciences in the 318
Carpathians, Miskolc Hungary. Acta Mineralogica-Petrographica, Abstract series, 5, 86. 319
Hirtopanu, P., Fairhurst, R.J., and Jakab, G. (2015) Niobian rutile and its associations at Jolotca, 320
Ditrau Alkaline Intrusive Massif, East Carpathians, Romania. Proceedings of the Romanian 321
Academy, Series B, 17, 39–55. 322
Jacob, D., Ji, G., and Morniroli, J.P. (2012) A systematic method to identify the space group from 323
PED and CBED patterns part II--practical examples. Ultramicroscopy, 121, 61–71. 324
Jambor, J.L., Burke, E.A., Ercit, T.S, and Grice, J.D. (1988) New mineral names. American 325
Mineralogist, 73, 1496-1497. 326
Martins, A.A.M., Andrade Filho, E.L.A, Loureiro, H.S.C., Arcanjo, J.B.A., and Guimarães, 327
R.V.B. (2008) Geologia da Chapada Diamantina Oriental (Projeto Ibitiara - Rio de Contas) - 328
Série Arquivos Abertos 31 - CPRM (Serviço Geológico do Brasil) and CBPM (Companhia 329
Baiana de Pesquisa Mineral), Salvador, 64 pp. 330
Menezes Filho, L.A.D., Chukanov, N.V., Rastsvetaeva, R.K., Aksenov, S.M., Pekov, I.V., 331
Chaves, M.L.S.C., Richards, R.P., Atencio, D., Brandão, P.R.G., Scholz, R., Krambrock, K., 332
Moreira, R.L., Guimarães, F.S., Romano, A.W., Persiano, A.C., Oliveira, L.C.A., and 333
Ardisson, J.D. (2015) Almeidaite, Pb(Mn,Y)Zn2(Ti,Fe3+)18O36(O,OH)2, a new crichtonite-334
group mineral, from Novo Horizonte, Bahia, Brazil. Mineralogical Magazine, 79, 269–283 335
Moore, M., Chakhmouradian, A.R., Mariano, A.N., and Sidhu, R. (2015) Evolution of rare-earth 336
mineralization in the Bear Lodge carbonatite, Wyoming: Mineralogical and isotopic 337
evidence. Ore Geology Reviews, 64, 499-521. 338
Morniroli, J.P. (2013) Atlas of Electron Diffraction Zone Axis Patterns, p. 314. Available at: 339
http://www.electron-diffraction.fr. 340
Morniroli, J.P. and Steeds, J.W. (1992) Microdiffraction as a tool for crystal structure 341
identification and determination. Ultramicroscopy, 45, 219–239. 342
Nakamoto, K. (1997) Infrared and Raman Spectra of Inorganic and Coordination Compounds. 343
Part A: Theory and Applications in Inorganic Chemistry. John Wiley and Sons, New York. 344
Nakamoto, K. (2009) Infrared and Raman Spectra of Inorganic and Coordination Compounds. 345
Part A: Theory and Applications in Inorganic Chemistry. (Sixth edition). John Wiley and 346
Sons, New Jersey. 347
Ni, Y, Post, J.E. and Hughes, J.M. (2000) The crystal structure of parisite-(Ce), Ce2CaF2(CO3)3. 348
American Mineralogist, 85, 251-258. 349
Pedrosa-Soares, A.C., Campos, C., Noce, C.M., Silva, L.C., Novo, T., Roncato, J., Medeiros, S., 350
Castañeda, C., Queiroga, G., Dantas, E., Dussin, I., and Alkmim, F. (2011) Late 351
Neoproterozoic-Cambrian granitic magmatism in the Araçuaí orogen (Brazil), the Eastern 352
Brazilian Pegmatite Province and related deposits. Geological Society of London Special 353
Publications, 350, 25-51. 354
Ranieri, I.M., Baldochi, S.L., and Klimm, D.(2008) The Phase Diagram GdF3–LuF3. Journal of 355
Solid State Chemistry, 181(5), 1070-1074. 356
Redjaïmia, A. and Morniroli, J.P. (1994) Application of microdiffraction to crystal structure 357
identification. Ultramicroscopy, 53, 305–317. 358
Sulovský, P. (2001) Accessory minerals of the Třebíč durbachite massif (SW Moravia). 359
Mineralia Slovaca, Košice: SGS, 33(5), 467-472. 360
Teixeira, L.R. (2005) Projeto Ibitiara - Rio de Contas, Estado da Bahia. Programa Recursos 361
Minerais do Brasil, Litogeoquímica, CPRM (Serviço Geológico do Brasil) and CBPM 362
(Companhia Baiana de Pesquisa Mineral), Salvador, 33 pp. + xv. 363
Theye, T., Ockenga, E., and Bertoldi, C. (2003) Davidite(-La), bastnaesite(-La), parisite(-La), 364
monazite(-La): REE minerals at a metabauxite/marble interface in eastern Samos (Greece). 365
Berichte der Deutschen Mineralogischen Gesellschaft, Beihefte zum European Journal of 366
Mineralogy Vol. 15, No. 1. 367
ftp://ftp.gmg.rub.de/pub/geo2003/17%20Quantification%20and%20dating%20of%20metam368
orphic%20processes%20WILLNER/Theye.PDF 369
White, W.B. (1974) The carbonate minerals. In: (Farmer, V.C., ed.) Infrared spectra of minerals. 370
Mineralogical Society Monography, 4, 227-284. 371
372
373
374
375
Table 1. Chemical data for parisite-(La). 376 377 378
379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399
1 constitu
ent wt.% range
stand. dev.
probe standard xtal line
CaO 10.10 10.05-10.15 0.02 wollastonite PET Kα
Y2O3 0.52 0.47-0.55 0.02 YAG TAP Lα
La2O3 24.77 24.54-24.96 0.11 REE3 LIF Lα
Ce2O3 11.16 11.03-11.32 0.07 REE3 LIF Lα
Pr2O3 4.73 4.63-4.91 0.06 REE3 LIF Lβ
Nd2O3 15.82 0.09 REE2 LIF Lβ
Sm2O3 1.25 0.03 REE2 LIF Lβ
Eu2O3 0.07 0.03 REE1 LIF Lβ
F 7.30 0.18 MgF2 TAP Kα
CO2 (24.50) (calculated)*
–O=F – 3.07 - -
Total 97.15
400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421
1. Analyses at the Department of Geosciences, University of Arizona, Tucson, Arizona, 422 U.S.A. 423
2. Analyses at the Instituto de Geociências, Universidade Federal de Minas Gerais, Belo 424 Horizonte, Minas Gerais, Brazil. 425
426 *calculated from the idealized formula. 427 Probe standard composition: 428 YAG = Y : 44.93%, Al: 22.73%, O: 32.34% 429 REE1 = Si: 12.60%, Al: 16.15%, Ca: 17.98%, Eu: 3.8%, Gd: 3.87%, Tb: 3.78%, Tm: 3.81%, O: 430 38.01% 431 REE2 = Si: 12.65%, Al: 16.21%, Ca: 18.05%, Nd: 3.65%, Sm: 3.67%, Yb: 3.74%, Lu: 3.75%, O: 432 38.27% 433 REE3 = Si: 12.69%, Al: 16.26%, Ca: 18.1%, Y : 3.21%, La: 3.65%, Ce: 3.42%, Pr: 3.79%, O: 434 38.88% 435 436
437 438
2 constitu
ent wt.% range
stand. dev.
probe standard xtal line
CaO 9.45 9.28 – 9.73 0.16 wollastonite PETJ Kα
Y2O3 0.51 0.48 – 0.54 0.02 YAG TAP Lα
La2O3 24.82 24.31 – 25.32 0.41 monazite-(Ce) PETJ Lα
Ce2O3 12.99 12.86 – 13.24 0.16 monazite-(Ce) PETJ Lα
Pr2O3 7.95 7.27 – 8.83 0.53 monazite-(Ce) LIF Lβ
Nd2O3 14.77 14.23 – 15.26 0.38 monazite-(Ce) LIF Lβ
Sm2O3 1.24 1.22 – 1.27 0.02 monazite-(Ce) LIF Lβ
Eu2O3 0.07 0.02 – 0.09 0.03 monazite-(Ce) LIF Lβ
F 6.71 6.01 – 7.58 0.48 MgF2 TAP Kα
CO2 (24.70) - - (calculated)*
–O=F – 2.82 - -
Total 100.39
Table 2. Powder X-ray diffraction data of parisite-(La). 439 440
Iobs dobs, Å dcalc, Å h k l* 55 13.95 13.991 002 20 6.98 6.995 004 37 4.655 4.664 006 88 3.555 3.561, 3.558 020, -311 13 3.446 3.451, 3.449, 3.448 022, 311, -313 3 3.323 3.326, 3.325, 3.324 023, 312, -314 18 3.169 3.173, 3.172, 3.171 024, 313, -315 12 3.000 3.004, 3.003, 3.002 025, 314, -316 100 2.827 2.830, 2.829, 2.828 026, 315, -317 2 2.655 2.659, 2.658, 2.657,
2.657 027, 316, -318, 404
2 2.495 2.495, 2.495, 2.494 028, 317, -319 8 2.331 2.332 0.0.12 1 2.274 2.275, 2.274, 2.271 -133, -424, -229 2 2.241 2.246, 2.245 133, 422 10 2.199 2.200, 2.200, 2.199 0.2.10, 319, -3.1.11 58 2.055 2.055, 2.054 -331, -602 4 2.034 2.033, 2.032, 2.032 -333, 600, -604 6 1.971 1.972, 1.972, 1.971,
1.971 333, -335, 602, -606
38 1.950 1.951, 1.951, 1.950 0.2.12, 3.1.11, -3.1.13 36 1.880 1.881, 1.881, 1.880,
1.879 335, -337, 604, -608
9 1.780 1.780, 1.779 040, -622 2 1.767 1.772, 1.772, 1.771 337, -339, -6.0.10 1 1.749 1.749 0.0.16 3 1.725 1.725, 1.724, 1.724 044, 622, -626 23 1.663 1.663, 1.662, 1.662 046, 624, -628 3 1.570 1.570, 1.570, 1.569 0.2.16, 3.1.15, -3.1.17 12 1.542 1.542, 1.542, 1.542,
1.541 3.3.11, -3.3.13, 6.0.10, -6.0.14
2 1.502 1.502, 1.502, 1.501 0.4.10, 628, -6.2.12 9 1.425 1.425, 1.425, 1.424 0.2.18, 3.1.17, -3.1.19 9 1.415 1.415, 1.415, 1.414 0.4.12, 6.2.10, -6.2.14 9 1.346 1.346, 1.345, 1.345 -351, -642, -913 3 1.332 1.332, 1.332, 1.332 3.3.15, 6.0.14, -3.3.17
*The hkl indices are chosen taking into account intensities of reflections of the powder X-ray 441 diffraction pattern calculated from the structure data for monoclinic parisite-(Ce) reported by Ni 442
et al. (2000). 443 444
445
Table 3. Comparative data for parisite-(La) and parisite-(Ce). 446 Parisite-(La) Parisite-(Ce)
Formula CaLa2(CO3)3F2 CaCe2(CO3)3F2 Space group C2, Cm, C2/m C2/c or Cc
a, Å b, Å c, Å
Z
a = 12.3563(13) b = 7.1368(7)
c = 28.299(3) Å β = 98.342(4)º
Z = 12
a = 12.305(2) b = 7.1053(5) c = 28.250(5) β = 98.257(14)°
Z = 12 Strong lines of the X-ray powder-diffraction
pattern: d, Å (I, %)
2.827 (100), 3.555 (88), 2.055 (58), 13.95 (55), 1.950 (38), 4.655
(37), 1.880 (36)
3.565 (100), 2.838 (100), 2.060 (80),
1.938 (60), 1.882 (50), 1.658 (50), 14.03 (40)
Optical data: ω ε
Optical sign
1.670(2) 1.782(5)
(+)
1.6718–1.6767 1.7664–1.7729
(+) Density, g·cm-3
4.331 4.3915
Mohs hardness 4 - 5 4 ½ References This study Cell data: Ni et al.
(2000); XRPD: Cheang (1977);
optical data, density, hardness: Flink (1901)
447 448
449 Figure 1. The Espinhaço Range in Eastern Brazil (states of Bahia and Minas Gerais), showing its 450 geographic/geotectonic domains Southern Espinhaço (SE), Central Espinhaço (CE), Northern 451 Espinhaço (NE) and Chapada Diamantina (CD) in relation to the São Francisco Craton (SFC). 452 The study area near Novo Horizonte (Bahia) is underlined. 453
454 455 456 457
458 459
460 Figure 2a – Partial pseudomorphs of monazite-(La) [M], bastnäsite-(La) [B], and rhabdophane-461
(La) [R] after parisite-(La) [P]. 462
463 464 465
466 467
Figure 2b – Crust consisting of microcrystals of parisite-(La). 468 469 470 471 472
473 474
Figure 3. Powder infrared spectra of (a) parisite-(La) and (b) parisite-(Ce) with the empirical 475 formula Ca1.08(Ce0.93La0.47Nd0.32Pr0.06Y0.08Th0.06)Σ=1.92(CO3)3.00F1.88 from White Cloud Mine, 476
Pyrites, Ravalli Co., Montana, USA. 477 478
479 480 481 482
483 Figure 4 – Raman spectrum of parisite-(La). 484
485
486 Figure 5. TG curve of parisite-(La). 487
488 489 490
491
492 Figure 6 – Electron diffraction zone axis pattern of highest “net”-symmetry found in parisite-493
(La), required for the identification of the crystal system. 494 495
496 Figure 7 – Electron diffraction of the either [010]b or [001]c zone axis required for the 497 identification of the Bravais lattice for the monoclinic crystal system. (a) Only the ZOLZ 498 reflections are visible. The lines indicate the symmetry axis in the pattern. (b-c) Both ZOLZ and 499 FOLZ reflections are visible after the electron beam had been tilted along each axis shown in (a). 500 The narrow parallelogram drawn in each figure corresponds to the “unit” cell in reciprocal space 501 in the ZOLZ and FOLZ. The relative shift of the “unit” cell in the FOLZ, along each symmetry 502 axis, compared to the ZOLZ is an evidence for a non-primitive crystal system. There is no 503 periodicity difference between ZOLZ and FOLZ reflections. 504 505
506